DE 10 2010 048 642 A1 discloses a motor vehicle of the type in question having a radiator arrangement, which has a radiator grille with a cooling air inlet and has a radiator arranged behind the cooling air inlet when viewed in the direction of travel. In addition, a flow-directing device is provided, which directs a cooling air flow from the cooling air inlet to the radiator. Here, this flow-directing device forms an air duct which is closed at the outer circumference and, in particular, is intended to prevent heated cooling air that has already flowed through the radiator and is flowing back in the direction of the cooling air inlet from re-entering an inflow region of the radiator. The intention is to achieve improved cooling capacity by this means.
In general, the air mass flow through the radiator of a motor vehicle can be produced by a fan or, alternatively, by the dynamic pressure of the moving motor vehicle. However, if there are gaps between the radiator and a cooling air inlet situated on the radiator-grille side of the motor vehicle, an unwanted bypass flow can arise, bypassing the radiator and thereby reducing the cooling capacity thereof. In addition, a high pressure can arise on the outflow side of the fan owing to the operation of said fan, particularly when a motor vehicle is stationary, said pressure ensuring that a recirculatory flow arises through gaps between the radiator and the radiator grille, carrying heated cooling air back to the radiator and thereby likewise reducing the cooling capacity thereof.
The flow-directing device known from the prior art is only suitable for use with a passenger vehicle and cannot be used in a commercial vehicle, owing to the specific installation geometry thereof.